Staff: Mentor

I think what they are trying to say is this: A mechanical wave transfers energy through a medium, but the medium itself does not get transferred from one point to another. Like sound energy travels through the air, but the air itself doesn't travel. (It just vibrates back and forth.) Or a ripple of a water wave traveling outward without the water itself moving outward.

(Don't worry about relativistic effects, if that's what you are thinking.)

I understand the role of a medium for a mechanical wave, and that there is an absence of a medium for an electromagnetic wave moving through free space, or more to the point, the medium is ( though not a true medium ) the oscillations in the elctronic and magnetic fields.

I apreciate your reply, but i am worrying about relativistic effects :) maybe you can help clear my confusion a little.

Another thing that bothers me, is, hypothetically speaking, assuming the parallel postulate to be flase, what effect would such a condition have on the EM wave model?